The present invention relates generally to an optical probe, particularly an optical probe for use in determining a position of an image sensor in a digital camera, whereby the image sensor can be positioned to provide a focused image.
In a typical digital camera, an image beam is directed through a lens and onto an imager or image sensor, for example a CCD (Charge Coupled Device), comprised of an array of sensing elements. The lens and the CCD need to be properly positioned relative to each other within the digital camera to provide a focused image. In order to properly position the CCD, the position of the CCD needs to be determined. Such a position can be determined relative to a reference surface or reference plane on the digital camera.
U.S. Pat. No. 5,757,485 (Marcus et al) and U.S. Pat. No. 5,757,486 (Marcus et al), commonly assigned and incorporated herein by reference, relate to a digital camera image sensor positioning apparatus and method which includes a non-coherent light interferometer. The apparatus and method include an optical probe assembly removably mountable to a digital camera. The non-coherent light interferometer is in communication with the optical probe assembly to determine a depth from a reference surface to the image surface and optical probe assembly. The apparatus and method have been suitable for their intended purpose, however, certain components of the optical probe assembly require gentle handling, for example, the pellicle. To utilize the apparatus and method in a manufacturing environment, such gentle handling may not be present. Thus, a robust design is needed. Accordingly, a need continues to exist for an optical probe assembly which is robust, has a simple construction, can be readily assembled and aligned, and can be used in a manufacturing environment, particularly by novice users. Further, a need exists to improve the angular acceptance cone of the optical probe to enable measurement of imagers which have a larger degree of tilt with respect to the ideal plane of the imager.
An object of the present invention is to provide a robust optical probe assembly which can be used in determining a position of an image sensor in a digital camera.
Another object of the invention is to provide such a robust optical probe assembly which is transportable, simple to use, low in cost, and can be readily mounted to a digital camera.
Yet another object of the invention is to provide such an optical probe assembly which is easy to manufacture, has a simple construction, and can be readily assembled and aligned.
Still another object of the invention is to improve the angular acceptance cone of the optical probe to enable measurement of imagers tilted with respect to the focal plane.
These objects are given only by way of illustrative example. Thus, other desirable objectives and advantages inherently achieved by the disclosed invention may occur or become apparent to those skilled in the art. The invention is defined by the appended claims.
According to one aspect of the present invention, there is provided an optical probe apparatus for determining a position of an image sensor in a digital camera relative to a reference surface on the digital camera. The optical probe assembly comprises a probe mounting surface, an angle cleaved optical fiber emitting a beam of light, a lens, a mounting member, and an optically transparent material. The probe mounting surface is adapted to be removably mountable to the digital camera and lockable in a predetermined orientation relative to the reference surface of the digital camera. The lens is disposed in the path of the beam of light and directs the beam of light along an axis normal to a plane of the lens toward the object. The mounting member supports the optical fiber such that the beam of light is directed along an axis normal to the plane of the lens and directed to the center of the lens. The optically transparent material is disposed intermediate the probe mounting surface and the image sensor. The optically transparent material may be a pellicle or a glass plate.
According to another aspect of the present invention, there is provided an optical probe apparatus for measuring a physical distance between a reference surface on a digital camera and an object disposed within the digital camera. The optical probe assembly comprises a probe mounting surface, an angle cleaved optical fiber oriented to emit a beam of light along an axis normal to the reference surface toward the object, a lens, a mounting member, and an optically transparent material. The probe mounting surface is adapted to be removably mountable to the digital camera and lockable at a predetermined distance from and in a predetermined orientation relative to the reference surface of the digital camera. The lens is disposed in the path of the beam of light and directs the beam of light along an axis normal to a plane of the lens toward the object. The mounting member supports the optical fiber and the lens such that the beam of light is directed along an axis normal to the plane of the lens and directed to the center of the lens. The optically transparent material is disposed intermediate the probe mounting surface and image sensor. The optically transparent material may be a pellicle or a glass plate.
The present invention provides an optical probe assembly suitable for determining the position of an image sensor in a digital camera. The optical probe assembly is robust, transportable, simple to use, and reduced in cost.